With wide application of aluminum alloy wheels, the category and the model are increasing. Some products are a little different and even same in front spoke shape, but different in size, wheel width and offset, e.g., 16×6.0 inches and 17×6.0 inches, 19×8.5 inches and 19×9.0 inches. The front shape is identical, but the sizes and widths of the wheels are different, so the wheels are unlikely to fast distinguish from the appearance only. In actual machining, some operators use blanks mistakenly to cause the accident of colliding with machine tools. On the basis of the current situation, the present patent provides a wheel blank outer rim scribing device, which can be used for machining groove ridges on a ring of outer rim of a wheel blank, and an operator can fast distinguish similar blanks via the number of the ridges, so that machining accidents caused by mistakenly using blanks are avoided; moreover, the device can also be used for recognizing blanks having large rim deformation.